docs: def clean_file(configuration, filename):
      """
      Strips out the warning from a translated po file about being an English source file.
      Replaces warning with a note about coming from Transifex.
      """
      pofile = polib.pofile(filename)
  
      if pofile.header.find(EDX_MARKER) != -1:
          new_header = get_new_header(configuration, pofile)
          new = pofile.header.replace(EDX_MARKER, new_header)
          pofile.header = new
          pofile.save()